Not applicable.
Not applicable.
The present invention relates generally to fasteners, and more specifically to a rotation restraining device for use in limiting rotation and loosening of threaded fasteners.
Although threaded fasteners are commonly used in industrial applications, environmental factors associated with such industrial applications can adversely affect the effectiveness of such fasteners. Industrial applications, for example, often include dynamic loading and motive devices that cause vibration and xe2x80x9cshockxe2x80x9d forces that affect mechanical joints formed by such fasteners. In addition, many industrial applications require motors, generators, and other industrial devices that generate excessive amounts of heat and therefore temperatures and related humidities in industrial environments are difficult to control.
Vibrational and shock forces, cyclical heating levels, and other environmental conditions have been known to cause threaded fasteners to rotate and loosen. While rotation of threaded fasteners has always been problematic, the loose fastener problem has become exacerbated recently as more industrial equipment is constructed from plastic. This is because plastic deforms and relaxes more readily than other rigid materials when subjected to adverse industrial application environments.
Complicating matters, threaded fasteners are often difficult to access inside equipment. Factory and industrial installations, for example, are often short on space, and industrial equipment, therefore, is designed to minimize size rather than to provide adequate access to fasteners. Furthermore, to save floor space, equipment is often installed in locations that are difficult to access.
For these reasons it would be advantageous to have a fastener assembly that would essentially lock threaded fasteners in their fastening positions.
It has been recognized that a simple restraining device can be provided to lock threaded fasteners in their fastening positions by providing an elongated member that forms a recess at one end and a restraining surface at another where the recess is sized so as to receive one end of a fastener and the restraining surface is formed so as to abut a surface of a receiving member (i.e., the member that receives the fastener) such that the elongated member cannot rotate in the direction corresponding to the loosening direction for the fastener. A fluid adhesive is provided within the recess and around the fastener end and forms a solid that fills the space between the recess surface and the received end.
An exemplary embodiment of the invention includes an apparatus for use with a fastener and a receiving member, the fastener including a first end and a threaded extension that extends from the first end, the receiving member forming an aperture along an axis for threadably receiving the extension and also forming at least a first surface that is essentially parallel to the axis and that is at least in part non-concentric with the aperture. The threaded member is removable from the aperture via rotation in a first direction. The apparatus comprises a bracket member including at least a securing segment and an extending segment that are integrally linked, the securing segment forming a recess, the extending segment extending laterally from the securing segment and forming a restraining surface. The apparatus also includes a bonding material that becomes solid and flexible upon curing, the bonding material provided within the recess.
With the threaded member received within the aperture and un-cured bonding material within the recess, the bracket member is positionable such that the first end is receivable within the recess and the restraining surface contacts the first surface, the surfaces together restrain rotation of the bracket member in the first direction about the axis.
Thus, one object is to provide an apparatus for limiting or restricting rotation of a threaded fastener. A related object is to prevent fasteners from becoming loose.
Another object is to provide a fastener restraining device that can easily and relatively quickly be installed. To this end the recess can be relatively larger than the received fastener end as the cured adhesive fills in the remaining gap. Thus, the device can be installed without having to precisely align a fastener end with the receiving recess.
One other object is to provide a device that can be installed without requiring tools. As indicated above no additional tools ar eurd to install the present device.
Moreover, yet another object is to provide a restraining system that can be used with many different fastener types. To this end the recess can be oversized so that various fastener head sizes (i.e., small and large) and shapes (i.e., square, hexagonal, octagonal, standard of Philips screw, etc.) can be accommodated. Again, the adhesive fills in the space between the head and the recess surface to form a secure bond.
In one embodiment an inwardly extending lip is provided along the recess opening. The lip serves to ensure that the solid adhesive stays within the recess during curing. In addition, if the bond between the adhesive and the fastener head and the recess surface fails, the lip traps the solid adhesive within the recess.
In one aspect a boss extension may be provided within the recess to maintain a space between the portion of the recess surface adjacent the boss and the fastener. Thus, another object is to provide a locking device of the above kind where adhesive contacts a large surface area of each of the recess and fastener surfaces thus forming a superior bond.
In one aspect the recess is defined by a recess surface that includes at least one radial incongruity wherein the phrase xe2x80x9cradial incongruityxe2x80x9d means that, given alignment of the recess with a fastener aperture, from the perspective of the aperture at least one portion of the surface is different than other portions. For example, in some embodiments the recess may form a main cavity and one or more lateral cavities that open into the main cavity. As another example the recess may define an extension into an otherwise cylindrical recess. The in-congruous surface or segment or member operates, in conjunction with the solid adhesive, to mechanically restrain the fastener. Also, in this regard, the apparatus is especially useful in conjunction with fasteners where the fastener portion received within the recess includes a radial incongruity.
In one embodiment the extending segment includes first, second and third extending segments, each of the extending segments being an essentially elongated flat member, the first extending segment linked to the secure segment at one end, the second extending segment extending from an end of the first extending segment opposite the securing segment, essentially perpendicular to the first extending segment and to the side of the first extending segment on which the recess opens, the third extending segment extending from an end of the second extending segment opposite the first extending segment and essentially parallel to the first extending segment, the third extending segment forming the restraining surface.
The invention also includes an apparatus for use with first and second. fasteners and a receiving member, each fastener including a first end and a threaded extension that extends from the first end, the first ends forming first and second essentially oppositely facing surfaces that define a first dimension. In this embodiment the apparatus is for restraining rotation of the fasteners when the extensions are received within apertures.
Here the apparatus comprises a bracket member including first, second and third integrally linked extending members, each of the first and third members including proximal and distal ends and forming first and second facing recesses at the distal ends, respectively, the second member linked at opposite ends to the first and third member proximal ends, respectively, the second distal ends defining a second dimension and preferably, where boss extensions are included, the boss extensions form the second dimension.
The apparatus also includes a bonding material that becomes solid and flexible upon curing, the bonding material provided within the recesses. With the threaded members received within the apertures and un-cured bonding material within the recesses the bracket member is positionable such that the first ends of the first and second fasteners are receivable within the recesses. Preferably the second dimension is less than the first dimension.
The invention also includes a method for use with a fastener and a receiving member, the fastener including a first end and a threaded extension that extends from the first end, the receiving member forming an aperture along an axis for threadably receiving the extension and also forming at least a first surface that is essentially parallel to the axis and that is at least in part non-concentric with the aperture, the threaded member removable from the aperture via rotation in a first direction. The method is for restraining rotation of the fastener when the extension is received within the aperture. The method comprises the steps of providing a bracket member including at least a securing segment and an extending segment that are integrally linked, the securing segment forming a recess, the extending segment extending laterally from the securing segment and forming a restraining surface; placing a fluid bonding material that becomes solid and flexible upon curing within the recess; with the threaded member received within the aperture, positioning the bracket such that the first end is receivable within the recess and the restraining surface contacts the first surface, the surfaces together restrain rotation of the bracket member in the first direction about the axis; and allowing the bonding material to cure.
Furthermore the invention includes a method for use with first and second fasteners and a receiving member, each fastener including a first end and a threaded extension that extends from the first end, the receiving member forming first and second essentially oppositely facing surfaces and the first ends defining a first dimension. The receiving member also forming first and second apertures along first and second essentially parallel axis for threadably receiving the first and second fastener extensions, respectively. The method is for restraining rotation of the fasteners when the extensions are received within the apertures. The method comprises the steps of: providing a bracket member including first, second and third integrally linked extending members, each of the first and third members including proximal and distal ends and forming first and second facing recesses at the distal ends, respectively, the second member linked at opposite ends to the first and third member proximal ends, respectively, the second distal ends defining a second dimension when the bracket is in an unstressed state; placing a fluid bonding material that becomes solid and flexible upon curing within the recesses; with the threaded members received within the apertures, positioning the bracket such that the first ends of the first and second fasteners are receivable within the recesses; and allowing the bonding material to cure.
Thus, one other object is to provide a bracket device that can lock more than one threaded fastener in place.
These and other objects, advantages and aspects of the invention will become apparent from the following description. In the description, reference is made to the accompanying drawings which form a part thereof, and in which there is shown a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention and reference is made therefor, to the claims herein for interpreting the scope of the invention.